Many show up early in the day for free tickets to hear the 'rock star' of physics speak, in what has become an annual appearance at the Pasadena campus.

If some L.A.-area teachers wondered where their students were Tuesday, maybe they can blame Stephen Hawking.

With his computerized voice, motorized wheelchair and an intellect that seems to leave mortal men far behind, Hawking is one of the best-known physicists ever. Die-hard fans, many of them youthful, started lining up early in the morning to get coveted free tickets to hear him speak at Caltech Tuesday night, school be damned.

FOR THE RECORD: Stephen Hawking: A Jan. 19 article in LATExtra on a talk at Caltech given by physicist Stephen Hawking said he has a form of muscular dystrophy that is related to amyotrophic lateral sclerosis. He has amyotrophic lateral sclerosis. —

"He'll have much better things to say than our teachers," said Palomar College engineering student Ashley Davis, who skipped class to drive up from San Marcos with three classmates for what has become an annual event at the Pasadena campus.

"It's like seeing the nerd pope!" offered Evan Hetland, 13, a self-professed physics fan who came with the Shatkin family of Valencia. Fifteen-year-old Steven Shatkin sat nearby in a chair doing his science homework, holding the enviable second-position-in-line for his family, huddled in the shade.

By 2:30, three dozen people were sitting outside Beckman Auditorium, chatting with friends, playing cards and reading books. One woman did needlework.

"We figured this was a once-in-a-lifetime chance," said Marilyn Joslyn of Los Angeles, who'd arrived with three friends early enough to nab the first place in line. Another pal came by with crackers and cheese to help them pass the time.

"I don't think we'd stand in line this long for our favorite rock star," Joslyn said.

To many among the nerd set, of course, Hawking is a rock star. With a brain the size of a planet locked in a body that has cheated him of movement and speech, and with appearances on television shows including "Star Trek" and "The Simpsons," he has captured the imagination of masses of people who often have little idea what his research is about.

For 30 years, he held the Lucasian Chair of Mathematics at the University of Cambridge, the same chair held by Isaac Newton in the late 1600s. Hawking gave it up in October 2009 when he reached the university's retirement age.

Now 69, his specialty is cosmology, the study of the universe, with particular emphasis on what is known as quantum gravity. He is probably most famous for his 1974 prediction that black holes should thermally create and emit subatomic particles, known today as Bekenstein-Hawking radiation, until they exhaust their energy and dissipate. In August 2009, he was awarded the U.S. Medal of Freedom, the nation's highest civilian honor, by President Obama.

Hawking has used a wheelchair since the early 1970s because of a form of muscular dystrophy related to amyotrophic lateral sclerosis that has progressed over the years and has left him almost completely paralyzed.

In April 2007, he made a zero-gravity flight in a modified Boeing 727, during which he experienced weightlessness eight times. It was the first time in 40 years that he moved freely. Hawking said it was in preparation for a planned suborbital spaceflight on Virgin Galactic's space service. Virgin's billionaire owner, Richard Branson, had pledged to pay for the flight.

The cosmologist created something of an uproar last year when he suggested that other intelligent species probably exist in the universe and that humans would be wise to avoid them. "If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn't turn out very well for the Native Americans," he said.

As the start of his Caltech talk drew near, the line had stretched to hundreds of people, some in wheelchairs, snaking down a campus path toward the street, a happy anticipatory hum in the air.

Hawking's entry to the auditorium and passage in his wheelchair along the red-carpeted aisle brought whoops and clapping. Several hundred who couldn't get in the hall sat on the lawn and steps and listened to the speech. His formal lecture, prepared in advance, was transmitted by a voice generator in its now-familiar robot-like American accent — one that Hawking, who is British, has commented upon wryly.

In addition to talking extensively about cosmology and his contributions to the field — he expressed special pride in his work on black holes — Hawking spoke of his life. He talked of his childhood and his parents: his upbringing in London and the town of St. Albans just north; of being not the greatest student as a young child — he didn't learn to read until he was 8 — but nonetheless being smart enough to earn the nickname "Einstein" from his classmates.

His father, a medical researcher, had wanted young Stephen to go into medicine also, but the boy had not felt the love. "The smartest people did math and physics," he said, to laughs from the audience.

His father, he added, had always had "a chip on his shoulder" from seeing others get ahead because of connections. "Physics is different than medicine," Hawking said. "It doesn't matter what school you went to or to whom you are related. It matters what you do."

Hawking added that he was very lazy while an undergraduate at Oxford. "I'm not proud of it," he said. He received his diagnosis while in graduate school; there were times, he said, when he didn't think he would survive to complete his PhD.

"When you are faced with the possibility of an early death," he said, "it makes you realize life is worth living and there are lots of things you'd like to do."